Date: Mon, 8 Dec 2014 22:33:46 +0100 From: Patrick Proniewski <patpro@patpro.net> To: Tom Samplonius <tom@samplonius.org> Cc: freebsd-scsi@freebsd.org Subject: Re: multipath problem: active provider chosen on passive FC path? Message-ID: <C9246F8D-076B-4D2D-93E4-C2FECC52B888@patpro.net> In-Reply-To: <81548287-A118-4AFD-8AB5-F76CD3B060FF@samplonius.org> References: <23F06C2E-558A-4E68-AD35-B3CD49760DFE@patpro.net> <81548287-A118-4AFD-8AB5-F76CD3B060FF@samplonius.org>
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On 08 d=E9c. 2014, at 21:03, Tom Samplonius wrote: >>=20 >> I've installed FreeBSD 9.3 on two HP blade servers (G6), into an HP = C7000 chassis. This chassis uses two Brocade FC switches (active/passive = if I'm not mistaken). The blade servers use=20 >=20 >=20 >> Unfortunately during boot, and during normal operation, the first = provider (da2 here) seems faulty: >>=20 >> isp0: Chan 0 Abort Cmd for N-Port 0x0008 @ Port 0x090a00 >> (da2:isp0:0:2:0): Command Aborted >> (da2:isp0:0:2:0): READ(6). CDB: 08 00 03 28 02 00=20 >> (da2:isp0:0:2:0): CAM status: CCB request aborted by the host >> (da2:isp0:0:2:0): Retrying command >=20 >=20 > FC switches are typically active-active, as the FC switch fabric is = "intelligent" and doesn't have looping issues like ethernet. >=20 > Your issue is probably on the storage array. Storage arrays = typically have an OS profile, and various advanced settings for how a = LUN is exported to a client. Storage arrays typically support SCSI = Reservations, where the LUN must be reserved before it can be used. = Also, storage arrays typically have multiple controller cards, and = typically an LUN is owned by one of the controllers at a time. The = storage array can signal to the client via SCSI that it wants to move = the the ownership to another controller. With proper client support, = migrating a LUN to another controller is typically hit-less.=20 >=20 > In your case, the storage array is probably configured to use one = controller/path at a time. And it is probably expecting to see specific = SCSI messages between itself and the host. These type of settings are = typically set by the OS profile. >=20 > Generally, storage arrays work best if you only send IO to one = controller at a time. And this involves co-ordination between the array = and the client using SCSI control messages. Though active-active paths = can usually be supported as well. Thank you for your reply. The SAN is an EMC VNX 5300. By default it = presents LUNs using ALUA as failover mechanism. I though GEOM could not = handle ALUA properly, so I changed the failover setting for this LUN, = now the FreeBSD hang during boot. If I boot in single user mode, it = boots completely but the result is the same default active path is not = functioning correctly. Tomorrow, I'll try another failover setting (dubbed "legacy"). The SAN = also allows me to specify initiator type (default to Clariion), I'll dig = into this setting to see if something exists that is more adapted to = FreeBSD host. Any other idea is welcome... Patrick=
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